In a conventional gas turbine engine, the air is compressed to high pressure and temperature by the compressor section. In this section, the vanes guiding the air to turn the compressor are frequently mounted on stems so they can be pivoted to adjust to various compressor flows and rotational speeds. The gases passing through the pivoted vanes are very hot, and the shrouds holding them are subject to thermal growth.
In recent years, new light weight ceramics and other composite materials have been developed which are very strong, lightweight and have superior high temperature wear and friction characteristics, and which, therefore, are useful in reducing the overall weight of many components. Such materials have utility in the shrouds used to support the pivoted vanes in the compressor. However, since many of the ceramic and other composite materials used in this application have almost no thermal growth, a problem is created in that other of the engine components do grow with temperature, and the failure of the shroud to grow in a similar manner can deteriorate engine performance. This invention obtains a desired thermal "growth" of a thermally unresponsive material by controlling such growth with a thermally responsive material.